Process for treating and brightening cellulose fibers



United States Patent "ice 3,356,524 PRUCESS FOR TREATING AND BRIGHTENING CELLULOSE FIBERS Bennett George Buell, Somerville, N.J., assignor to American Cyanamid Company, Stamford, Conn., a corporation of Maine No Drawing. Original application May 11, 1964, Ser. No. 366,635, now Patent No. 3,309,363, dated Mar. 14, 1967. Divided and this application Sept. 29, 1966, Ser. No. 583,086

2 Claims. (Cl. 117-335) ABSTRACT OF THE DISCLOSURE A DAS-triazine brightener of the formula (in H SO3X is applied to cellulose fibers simultaneously with conventional textile improving resins and cationic softeners.

This application is a division of copending application, Ser. No. 366,635, filed May 11, 1964.

This invention relates to an improved means of simultaneously brightening and improving cellulose fibers. More particularly, it relates to the provision of a new brightener which can be effectively applied to cellulose fibers such as cotton simultaneously with the application of conventional textile improving resins and cationic softeners. It relates further to the resulting cotton fibers.

Cotton fabrics are generally finished by treatment with resins which make the fibers crease-resistant and also impart good wash-and-wear properties. These resins may undesirably render the fabrics hard to the touch. It has become the practice to include in the resin-treating composition a material which counteracts this undesirable side effect. For this purpose, softeners, mostly of the cationic type, are employed. These softeners are generally quaternary ammonium salts which are soluble in the aqueous resin-treating solution.

In a typical operation the textile resin monomer of the amino-aldehyde (called also amino resin) or epoxy type, together with an acid-acting accelerator, is dissolved in an aqueous solution. T 0 this solution is added the quaternary ammonium salt to serve as softener. A cotton fabric is padded in the solution and cured at elevated temperatures to produce the finished fabric. The fabric is creaseresistant and, at the same time, is soft.

If it is desired to treat the fabric with an optical brightener, this treatment normally has to be performed as a separate padding step, since most known optical brighteners are not effective in the presence of the cationic 3,356,524 Patented Dec. 5, 1967 fin-ong-t ln-t im 2 on 011 This compound (or, equivalently, its ammonium or sodium or potassium salt) is surprisingly stable in an aqueous bath containing the conventional textile improving resins and cationic softeners. An aqueous padding bath having all three components leads to cotton fabrics which, in one step, are improved with respect to brightness, crease-resistance and softness. This is surprising since, as Will be shown hereinafter, chemical structures which are presumably closely related and which are useful optical brighteners in the absence of the cationic softener, lose their effectiveness to a great extent in the presence of a cationic softener. The compound of the present invention retains its effectiveness substantially completely.

The brightener of this invention is made by reacting 2 moles of cyanuric chloride in an alkaline solution with one mole of 4,4-diaminostilbene-2,2-disulfonic acid, followed by treatment with 4 moles of l-aminopropanediol- 2,3. The alkali used is preferably a hydroxide of an alkali metal such as sodium. The solution of the alkali salt of a compound of this invention may be used directly in the resin-softener application or the compound may be isolated as the free acid and later dissolved with an alkali hydroxide before application.

The brightener of the present invention may be applied with conventional textile improving resins. The preferred resin monomer is an amino resin, a type of resin monomer well-known in the art (see I. F. Blais, Amino Resins, New York, Reinhold, 1959, Chapter 7), which is used together with an acid-acting accelerator, which 'can be a salt of a strong acid, like zinc nitrate, zinc above-described resins may be used herein. Generally and preferably, they are quaternary ammonium salts such as a tetraalkyl ammonium salt. Preferred members of this type are dialkyl dimethyl quaternary ammonium chlorides in which the alkyl is a fatty residue such as stearyl, coco or tallow radicals.

Cotton fabrics are treated in accordance with the present invention by conventional means except that the optical brightener and the resin-softener treatment will be accomplished simultaneously. As an example of a useful operating procedure, the cloth is passed through a padding bath containing approximately 0.1% of the brightener, 10.0% of a resin monomer (50% type), 2.0%

of an accelerator (30% type) such as an acidic salt, 2.0% of a cationic softener type) and 0.10% of a wetting agent. It is then nipped in a roller to about 6580% pickup and dried at room temperature. It is finally cured for 1-2 minutes at 325 F. The resulting fabric has good dimensional stability and a good hand and with the brightener of this invention has outstanding whiteness.

In general, the brightener bath should contain from 0.01 to 1.0% of brightener based on the weight of the padding solution. On the same basis, the concentration of the cationic softener should be from 1 to of a 5% type.

The following examples, in which parts are by weight, are presented to illustrate further the present invention.

EXAMPLE 1 OH OH S0311 A solution is preparing containing:

4,4-diaminostilbene-2,2'-disulfonic acid grams 18.5

Water do 220 5 N sodium hydroxide solution milliliters 20 Acetone .do 100 The solution is cooled to 0 C. and treated rapidly with a solution at 0 C. of 18.5 grams of cyanuric chloride in 150 milliliters of acetone. The reaction is exothermic, the temperature rising to about 10 C. The mixture is cooled to 0 C. and stirred at this temperature until the reaction is complete. A solution of 40 milliliters of anhydrous sodium carbonate is added to bring the pH to about 5. The mixture is heated to 30 C. and treated with 36.4 grams of 1-aminopropanediol-2,3. The acetone is stripped off and the remaining solution heated at reflux until the reaction is complete. The whole is cooled to ambient temperature, acidified with 5 N hydrochloric acid solution and the product filtered, washed with ether and dried. Yield is 51.1 grams of product; A is 345 mp; absorptivity at this wave length is 46.2.

EXAMPLE 2 A solution of the compound of Example 1 is made by dissolving 100 mg. of the compound in 100 ml. of water with one drop of 30 Baum caustic soda solution and warming. The solution is cooled to ambient temperature, and there is added to the solution indicated amounts, on weight of the solution (O.W.S.), of the following:

Textile resin 10% dimethylolurea.

Accelerator 2% of a 30% solution of magnesium chloride.

Cationic softener 2% of a 5% solution of distearyl dimethyl ammonium chloride in the form of a 70% paste.

Water is added to a volume of 200 ml. Concentration of the compound of Example 1 in the padding solution is 0.05%.

80 x 80 (threads to the inch) percale cotton, about two yards, is given one dip and nip. Pickup is 80% solution on the weight of the fiber. The padded cotton is cured for two minutes at 325 F.

A highly chromatic white fabric of good hand and good dimensional stability is obtained. It is as white as a sample of cotton fabric padded with a solution having the brightener in the same concentration, but neither a resin nor a cationic softener.

4 EXAMPLE 3 When cotton is padded in a 0.05% padding solution of the brightener compound of Example 1 using the procedure of Example 2 and choosing one each of the following components in any combination, equally good results are obtained:

Highly chromatic white cotton fabric is obtained in each case.

EXAMPLE 4 Behavior of brightener of Example 1 in the presence of excess cationic softener This example shows the stability of the compound of Example 1 in the presence of excess concentrations of cationic softener.

A 0.05% padding solution of the brightener of Example 1 is prepared as in Example 2. The solution includes 0 the following instead of the resin, accelerator and softener recited therein:

Textile resin 12.0% O.W.S. of a resin mixture which is at least 75% methylated hexamethylol melamine.

Accelerator 2.4% O.W.S. of a 30% solution of magnesium chloride. Cationic softener 8.0% of a 5% solution of cationic softener GW of Proctor and Gamble, a quaternary ammonium salt.

The padding and curing procedure is followed as in Example 2.

A cotton fabric of good hand and comparable brightness to that of Example 2 is obtained. This shows that the brightener behaves well in the presence of excess cationic softener.

EXAMPLE 5 The compound of this invention is highly desirable in that it is stable in the presence of a cationic softener and remains in solution. Expectedly similar compounds lose strength in the presence of a cationic softener. Otherwiseuseful brighteners such as the last compound of the fol- 5 lowing table, even precipitate completely out of solution in the presence of a cationic softener. Thus, they cannot be used to treat cotton in the presence of a cationic softener.

Such compounds are shown in the following table. Effec- 7 tiveness for use as a cotton brightener from a padding bath containing cationic softener is measured as the percent loss of strength, using as standard the dyeing obtained from a bath having neither cationic softener nor resin.

The higher the loss, the less the effectiveness of the bright- 75 ener.

TABLE SOaNa X Z Remarks 0 CHzCHsOH NHCH3CHCH3 Loses -30% strength In resin-cationic softerner HO O H application.

CHzCHl 0 01130112011 Loses 25% when applied as above.

CHgCH:

CHaCHrO H OOH,0H=(OOH;OH;)xOOH OHzOH av. 6.8 N\ Lostes when applied as a ove. CHzCHzO H NH O (CHzOH);

-NH--C 5114- (S O rH-Ill) 20-30% loss when applied as above.

20-35% loss when applied as above.

Shows 20-30% strength loss from resin-softener application.

Preeipitates in presence oi cationic softener. Whitening efieot totally lost.

I claim:

ing of hydrogen, sodium, ammonium and potassium, and

1. A method of treating cotton fibers which comprises curing said resin at elevated temperature.

contacting said fibers with an aqueous solution having an efiective amount of a thermosetting textile resin, an eifective amount of a cationic softener and an effective amount of an optical brightener of the formula:

N 2875106 a s on @NHI Inn on. E: 2: 3,018,287 803x 3,309,363

NH-CHPCH-CHI 2 H n 2. The method of claim 1 wherein the textile resin is an amino resin and the cationic softener is a tetraalkyl ammonium salt.

References Cited UNITED STATES PATENTS 2/ 1959 Adams et a1. 117-335 1/'1962 Fleck 117-335 3/ 1967 Buell 260240 FOREIGN PATENTS 3/1954 Great Britain.

WILLIAM D. MARTIN, Primary Examiner. wherein X is a member selected from the group consist- T. G. DAVIS, Assistant Examiner. 

1. A METHOD OF TREATING COTTON FIBERS WHICH COMPRISES CONTACTING SAID FIBERS WITH AN AQUEOUS SOLUTION HAVING AN EFFECTIVE AMOUNT OF THERMOSETTING TEXTILE RESIN, AN EFFECTIVE AMOUNT IF A CATIONIC SOFTNER AND AN EFFECTIVE AMOUNT OF AN OPTICAL BRIGHTENER OF THE FORMULA: 